Photometer



C. STANG.

PHOTOMETER.

APPLICATION HLED sEPT.28.1918.

1,829,439. Patented Feb. 8,1920.

' 2 SHEETS-SHEET l. j'zl,

C. STANG.

PHOTOMETER.

APPLICATION FILED SEPT. 28| 1918.

Patented Feb. 3,1920.

` 2 sHEETs-sHEET 2 l 18 'zl UNITED sTA'rEs PATENT OFFICE.

CARL sTANG, or' 'oHIcAG iiiLiNois.

PHOTOMETER. 1,329,439, Specificaton of Letters Patent. Patented Feb, 3, 1920.'

Application filed Septembfcr 28, 1918. Serial No.

.To all wlwm it may camera:

Be it known that I, CARL STANG, a citizen o f the United States, and a. resident of tlie i'earward end of which is provided With a '-*iewing opening 12.

Formed in the front end of casing 11 is i 'city of Chicago, county of Cook, and State of an opening 13 for thc adn'iission of exter- .5 Illinois, have invented certain new and usenal light, a suitable transparency 14 of deful inpr'ovements in Photometers, of which sired opaqueness being arranged over the the .following is a specification. A innei side of said opening to effect proper y invention relates to photometers, that dffusion of the light passing therethrough is, devices designed for use to aid in ascer- Also formed in .the front end of casing 10 taining the correct time of exposure necesis an opening 15 in front of which is arsary in Jche takin of pictures. ianged an electric light bulb ,16 arranged ore material, and therefore mone is in an inclosed Chamber 17, the arrangement wasted by' amateur photographers throuoh being such that the light 16, when in operaerroi' in the time of exposure in the taking of tion, will be viewable through the opening 15 pictures than results from all other causes 15, from'the'viewing opening 12. Arranged and errors committed by amateui phowithin the casing 11 for coperation with tographers It is the object of th1s mvenie opening 15 and the light 16 is a rotatabl ion to provide a device through the medium mouhted disk "18 carried by an exteriorly of which a p otographer may readily and projecting stem orshaft 19. e disk 18 20 easily ascertain the proper time of exposure S formed with a plurality .of spaced openbefore taking a picture, thereby materially ings 20 adapted, upon rotation of said disk, assistinfr in obtaining successful results and to be brought into successivev registration .in the saving of money which otherwise is Wlth the Openlng 15, aS W111 be readly unwasted through improperly exposed films Clerstood. Arrange in eac opening 20 is 25` A furthcr object is the production of a dea transparency 21, the transparencies 21 of vice as mentioned, which will beA of durable the Various openings 20 being of varyinof deand economical construction and highly ef- -grees of epaqueness, the graduation in the ficient in use. w degrees of opaqueness of said transparencies Other objects will appear hereinaftcr. being secured through the use of a p1u- 30 ie invention consists in the -combina rality of layers of transparent lmaterial i tions and arrangements of parts hereinafter which comprise each transparency 21, as described and claimed. seen in Fig. 10, and by'varying the number he invention will bebest understood by of such layers in the various openings 20'. reference 130 the accompanying drawings It is, of course, apparent that the fewer the B5 forining a` part of this specification, and layers employed 111 each transparency the in which; i less opaque the transparency will be, the F igure 1, is a partially Vsectional top plan opaqueness being increased through the view of a photo meter embodying the inemployment of more layers. Thus, with this vention, arrangement, through rotary adjustment of 0 Fig. 2, a sideelevation thereof, 'the disk 18 carrying the various'transpar- Fig. 3, a longitudinal section through the encies 21 into registration with the openin evice, 15, more or less of thelight emanating from Fig. .4, a front elevation of the device, the lamp 16' may be cut ofl" and thus the in ig. 5, a rear elevation thereof, I tensity of this light, as viewed from the 5 Fig. 6, a front elevation of one of the viewing opening 12, varied as desired `transparencies used in connection with the The disk 18 is yieldinwly held in positions evice, of rotary adjustment by means of a resilient F ig. 7, a transverse section through the pawl 22 w ich is adapted for engagement device looking toward the front end therewith notches 23 formed in the periphery of of, and said disk. he outer end of the stem or F igs. 8, 9 and 10, sections 'taken on shaft 1,9 of said disk is provided with a lines 8+8, 9-9 and 10410, respectvely, knurled head 24 for effecting manual rotaof Fig. 7. tion thereof.` arried by said stem is a The preferred form of construction, as graduated disk 25 having graduations corillustrated in the drawings,

coniprises an elongated closed the transparency openings casing or housing 1.1, the

f t e disk 1.8, and coperating with the graduations on disks 25 is anv indicator or adjustment has finger 26.

In using the device, the operator holds the same pointing in the'direction of the object or scene to be photographed and looks through the viewing opening 12 toward the openings 13 and 15. When thus held, external light will pass through the opening 13 and artificial light will pass through the opening 15 emanating from the lamp 16. lVith the device thus held the operator, through engagement with the head 24 adjusts the disk 18 to such position that the light emanating from the lamp 16 will be of the same intensity oi' brilliancy as that passing through the opening 13. Then this been elfected, the operator consults the dial 25 to ascertain which graduation is registering with the indicator 26. The graduation having been determined, he then refers to a scale or table 27 provided upon the outer side of casing 11, where is shown the duration of the film exposure time, as for instance one-fiftieth lof .a second, one-fourth of a second, and the size of the diaphragm opening 'as for instance 32, 16, 22, etc., the camera being correspondingly adjusted, as will be readily understood.

VVhen the disk 18 is adjusted to allow for the maximum passage of light therethrough, the light permitted to be passed through the opening 13 should be exactly the same, on an ideal day, that is, one in which the actinic conditions are ideal.4 To secure this-initial adjustment, supplemental transparencies 28 may be inserted into slots 28' provided in the casing 11 at the openings 13 and 15, as olearly seen. in Figs. 1, 9 and 10.

The lamp 16 is aotuated through the medium of a dry cell 29, which is removably arranged in a chamber 30 provided at the under side of casing ing a suitable spring-held door 31. A suitably positioned control switch 32 is inter- 11, said Chamber havposed in the circuit of said lamp. As the dry cell 29 loses its strength, the light emanating from the lamp 16 will, of course, become less brilliant, necessitating the employment of the supplemental transparencies 28, as above referred to.

Vhile I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but

desire to avail myself of such variations and modifications as come within the .scope of the appended claims.

Having described my invention, what I claim'as new and desire to secure by Letters 'Patent is A photo meter comprising a a viewing opening and an opening for the admission of external light; a sourcevof light in said casing; means for varying the intensity of the light from said source for comparison with the light entering through said light admission opening, sald means comprising a movably mounted holder; a plurality of transparencies of graduated opaqueness carried by said holder adapted to be brought, successively into registration with said source of light; and supplemental adjustably mounted transparencies adapted for coperation with said source of light casing having and said light admission opening for varyof the .light einanating therefrom as seen from said viewing opening, substantially as described.

In testimony whereof I have signed niy name to this specification in the presence of two subscribing witnesses.

CRL STANG.

ing the intensity Witnesses:

ARTHUR A. OLsoN, JosHUA R. H. Po'rrs.v 

